package leetcode;

import java.util.Deque;
import java.util.LinkedList;

/**
 * 描述:2. 两数相加
 *
 * @author Madison You
 * @created 23:19
 */
public class Mid_2_AddTwoNumbers {

    public static void main(String[] args) {
        int[] arr1 = {2, 4, 9};
        int[] arr2 = {5, 6, 4, 9};
        ListNode node1 = createNode(arr1);
        ListNode node2 = createNode(arr2);
        ListNode listNode = addTwoNumbers(node1, node2);
        System.out.println(listNode);
    }

    public static ListNode createNode(int[] arr) {
        ListNode head = new ListNode(arr[0]);
        ListNode other = head;
        for (int i = 1; i < arr.length; i++) {
            ListNode temp = new ListNode(arr[i]);
            other.next = temp;
            other = other.next;
        }
        return head;
    }

    public static ListNode addTwoNumbers(ListNode l1, ListNode l2) {
        ListNode head = null, tail = null;
        int carry = 0;
        while (l1 != null || l2 != null) {
            int n1 = l1 != null ? l1.val : 0;
            int n2 = l2 != null ? l2.val : 0;
            int sum = n1 + n2 + carry;
            if (head == null) {
                tail = head = new ListNode(sum % 10);
            } else  {
                tail.next = new ListNode(sum % 10);
                tail = tail.next;
            }
            carry = sum / 10;
            if (l1 != null) {
                l1 = l1.next;
            }
            if (l2 != null) {
                l2 = l2.next;
            }
        }
        if (carry > 0) {
            tail.next = new ListNode(carry);
        }
        return head;
    }



}
